doi:10.1510/icvts.2011.281998
Interactive CardioVascular and Thoracic Surgery 13 (2011) 626-630
www.icvts.org
Best evidence topic - Coronary
Does a ‘no-touch’ technique result in better vein patency? Amir H. Sepehripoura, Omar A. Jarralb, Alex R. Shipolinib, David J. McCormackb,* a
Department of Cardiothoracic Surgery, Wythenshawe Hospital, Southmoor Road, Manchester M23 9LT, UK b Department of Cardiothoracic Surgery, The London Chest Hospital, Bonner Road, London E2 9JX, UK Received 28 June 2011; received in revised form 21 August 2011; accepted 24 August 2011
Summary A best evidence topic was written according to a structured protocol. The question addressed was whether harvesting the saphenous vein (SV) as a conduit for coronary artery bypass grafting (CABG) using a no-touch technique would result in better patency rates. This technique involves the harvest of the SV with a pedicle of peri-vascular tissue left intact and the avoidance of distension of the vein prior to anastomosis. A total of 405 papers were found using the reported searches of which eight represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. The studies found analysed the ultrastructural and mechanical properties of the endothelium and vessel walls of the two harvesting techniques; the protein and enzymatic expression and activity observed; the early atherosclerotic changes detected; and the overall patency of the grafts during short- and long-term angiographical follow-up. Three small prospectively randomised studies compared the patency of grafts harvested using the two techniques and found significant improvements in graft patency using the no-touch harvesting technique in comparison to both the conventional technique and more importantly comparable to the left internal thoracic artery (LITA) patency. The most favourable difference was that of graft patency after 8.5 years of follow-up [90% vs. 76% (P=0.01), LITA patency 90%], and incidence of graft stenosis [11% vs. 25% (P=0.006)]. These findings were supported by the demonstrated improvements in the cellular integrity of the vessels and the reduction in the mechanisms leading to graft failure seen in the no-touch harvested SV grafts. These morphological and cellular analyses were carried by five small comparative studies, demonstrating improved endothelial integrity and reduced injury, decelerated atherosclerotic processes, intact adventitial collagen layers, increase in the total area of vasa vasorum, elevated endothelial nitric oxide synthase expression and activity, and increased peri-vascular leptin levels and activity. We conclude that there are clear enhancements in vessel wall properties at a cellular level and angiographical evidence of superior graft patency when the no-touch SV harvesting technique is employed. 2011 Published by European Association for Cardio-Thoracic Surgery. All rights reserved. Keywords: Coronary artery bypass grafting; Saphenous vein harvest; Graft patency
1. Introduction A best evidence topic was constructed according to a structured protocol. This protocol is fully described in ICVTS [1]. 2. Clinical scenario A symptomatic 74-year-old female with angina on minimal exertion is referred for consideration of redo coronary artery bypass grafting (CABG). She had undergone her first bypass operation seven years ago where the left anterior descending artery, first diagonal branch, and the first obtuse marginal branch were revascularised using the left internal thoracic artery (ITA) and two conventio nally harvested saphenous vein (SV) grafts, respectively. There is now angiographical evidence of diffuse rightsided stenoses as well as occluded diagonal and obtuse marginal grafts. You consider the possible reasons for this
failure and contemplate the conduit options for repeat revascularisation. 3. Three-part question In [patients undergoing coronary artery bypass graft surgery] does harvesting the saphenous vein graft using a [notouch technique] rather than a [conventional technique] result in better vein graft patency? 4. Search strategy Medline from 1948 to May 2011 using the PubMed interface (‘touch’[MeSH] OR ‘touch’) AND (‘veins’[MeSH] OR ‘veins’ OR ‘vein’) AND harvesting AND patency AND (‘coronary artery bypass’[MeSH] OR (‘coronary’ AND ‘artery’ AND ‘bypass’) OR ‘coronary artery bypass’). Related articles and references were screened for suitable articles. 5. Search outcome
*Corresponding author. Tel.: +44-7811-116401; fax: +44-20-89832331. E-mail address:
[email protected] (D.J. McCormack). 2011 Published by European Association for Cardio-Thoracic Surgery
Four hundred and five articles were found using the reported search strategy. From these, eight articles were
A.H. Sepehripour et al. / Interactive CardioVascular and Thoracic Surgery 13 (2011) 626-630
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Table 1. Best evidence papers Author, date and country, Study type (level of evidence)
Patient group
Outcomes
Key results
Comments
Johansson et al., (2010) Eur J Cardiothorac Surg, Sweden, [2]
One hundred and four patients (281 grafts) randomised into two groups, NT and CT, and analysed in a short-term (18 months) and long-term (8.5 years) study
Graft patency at 18 months
One hundred and five grafts (89.0%) in NT group and 84 grafts (75.0%) in CT group normal on cineangiography
The superior long-term patency rate using the NT technique for SV graft harvest can be explained by a significantly slower progression of atherosclerosis compared to the conventional technique
Randomised controlled trial (level 2)
Short-term study: ninety-one patients (251 grafts) underwent cineangiographic follow-up; 45 patients (124 grafts) in the NT group and 46 patients (127 grafts) in the CT group. Patent grafts underwent IVUS (15 NT and 14 CT) Long-term study: seventy-four patients (202 grafts) underwent cineangiographic follow-up; 37 patients (101 grafts) in the NT group and 37 patients (101 grafts) in the CT group. Patent grafts underwent IVUS (27 NT and 26 CT)
Thirteen grafts (11.0%) in NT group and 28 grafts (25.0%) in CT group were stenosed (P=0.006) Graft patency at 8.5 years
Eighty-three grafts (91.2%) in NT group and 64 grafts (83.1%) in CT group normal on cineangiography
Early atherosclerotic changes on IVUS at 18 months
NT group vs. CT group: • less mean intimal thickness (0.43 mm vs. 0.52 mm, P=0.03) • less grafts with considerable intimal hyperplasia (≥0.9 mm) (20% vs. 78.6%, P=0.011) • less patients with considerable hyperplasia (≥0.9 mm) (25% vs. 100%, P=0.007) • larger graft lumen volumes (120.3 mm3 vs. 89.3 mm3, P=0.07)
Early atherosclerotic changes on IVUS at 8.5 years
NT group vs. CT group: • fewer grafts containing multiple plaques (14.8% vs. 50%, P=0.008) • less advanced plaque with lipid (11.8% vs. 63.9%, P=0.0004) • less maximal plaque thickness (1.04 mm vs. 1.32 mm, P=0.02) • fewer patients with grafts containing plaque (50% vs. 80%, P=0.13) • larger lumen volumes (135.8 mm3 vs. 109.7 mm3, P=0.03)
Graft patency at 18 months
Graft patency 95.4% in NT group (P=0.025), 86.2% in I group, 88.9% in CT group
One hundred and fifty-six patients undergoing CABG into 3 groups: CT, NT and intermediate
Prospective randomised study (level 2)
All patients received ITA grafts
ITA patency 91.5% across all groups
All patients commenced on aspirin at a dose of 160 mg/day postoperatively
Occlusion rates of low-quality veins were 10.3% in NT group, 31.6% in I group, 44.4% in CT group
I group: one hundred single grafts, 14 double sequential, 2 triple sequential, and 35 ITA grafts NT group: one hundred and nine single grafts, 15 double sequential and 42 ITA grafts One hundred and twenty-four patients (46 CT group, 41 I group, 45 NT group) underwent angiographic analysis
The endothelial integrity and eNOS activity are better preserved with the NT technique. The surrounding tissue provides mechanical protection and protects the SV from spasm, ischaemia and kinking; and the vasorelaxation and thromboresistant activities of nitric oxide all contribute to improved SV graft patency rates
Postoperative acute MI
Postoperative acute MI in 2 patients in CT group
Endothelial morphology
Significantly improved endothelial integrity in NT group (P
